1. Field of the Invention
This invention relates to a material testing device, especially,with a testing device and a testing method to measure brittle point, fracture strength, strain of fracture, viscosity and stress relaxation (relaxation modulus of elasticity) and so on in comparatively low strength's materials like asphalt, wax, resin and the paint and the food of chocolate and so on.
2. Description of the Related Art
As the method of measuring brittle point in the comparatively low strength's material like asphalt, wax, resin and the paint and the food of chocolate and so on, Fraass brittle point test method (JIS K2207 "PETROLEUM ASPHALT" 5.15 page; the conventional example 1) is known from the past.
In the above-mentioned conventional example 1, it is necessary to confirm an occurrence of crack in the material to be tested with the eyes through a test tube made from the glass. But, when the test tube becomes dim with cooling air, the such confirmation is difficult. Also, there is a problem that it is difficult to get high precision measurement results because it isn't possible to control the rate of cooling correctly.
As the method to improve these problems, the following methods are proposed; Fraass brittle point test method (Japanese Patent Application Publication Sho 64-11146; the conventional example 2) which catches a noise which accompanies the occurrence of crack in the tested material and detects temperature at this time; and another Fraass brittle point test method (Japanese Utility-model Application Laid-open Sho 63-145167; the conventional example 3) which makes the tested material curve repeatedly in liquid, and measures temperature of the liquid when crack occurs in the tested material.